1. Field of the Invention
The present invention relates generally to a flexible display device, and more particularly to a configuration of components at the curved portion of the flexible display substrate for reducing the effect of bending stress.
2. Discussion of Related Art
Display devices used in monitors of computers, TVs, and cell phones include organic light emitting display devices (OLEDs) and plasma display panels (PDPs), both of which autonomously emit light, and liquid crystal display devices (LCDs) requiring a separate light source, etc.
In recent years, flexible display devices manufactured to display an image even when bent like paper by forming a display unit and a wire on a substrate exhibiting flexibility, such as a flexible material (i.e., a plastic), have received attention as next-generation display devices.
Flexible display devices have been widely used in the field of applications spanning from monitors of computers and TVs to personal portable equipment, and research on flexible display devices having a large display area and a smaller volume and weight has been conducted.
When a flexible display substrates and/or devices are bent, mechanical stress (e.g., tensile or compression stress) is applied to the bent portion of the substrate as well as the components that are disposed on the bent portion, and such mechanical stress can cause cracking at certain weak point of the substrates and/or devices. Isolated crack at one point can propagate and channel across the substrate. If the substrate is brittle the crack may penetrate through the substrate, even though it is essentially unstressed. The interface of two regions, layers and/or portions of certain components may debond, or a debond crack may dive further into the substrate producing delamination via cracking parallel to the interface in the substrate.
Of course, such cracks and breakage can cause various problems in the device. Especially, the mechanical stress at the bent portion may crack or wholly disconnect some portions of the wires formed thereon, thereby causing various defects in the device.